This would keep the whole of the UK in the customs union to avoid a hard border in Ireland.

Irish Foreign Minister Simon Coveney has said the Irish position remains clear and a backstop that could be ended by the UK unilaterally would never be agreed to by Ireland or the EU.

On Twitter, Mr Coveney said: “The Irish position remains consistent and very clear that a ‘time-limited backstop’ or a backstop that could be ended by UK unilaterally would never be agreed to by Ireland or the European Union.”

This comes as the former Foreign Secretary Boris Johnson has described a proposed Brexit deal with the EU as an “absolute stinker” as he demanded MPs should reject it.

He was speaking about the speculation the Prime Minister had allegedly made a deal with Brussels allowing the creation of a whole-UK customs union.